LCD Technicalities: Do Contrast Ratios Matter?

Contrasts That Work For Photos And Games

Photographic Use

To make sure we weren't misinforming you, we took a short tutorial with Gerard Niemetzky, director of the Color Academy and author of the work "Calibration and ICC Profiles for Digital Imaging and Graphics Production Processes" published by Editions Eyrolles.

This well-known expert calibrates LCD screens at a color temperature of 5000°K, with white at 110 cd/sq m and black at 0.5 cd/sq. m.

A screen with these settings should produce a contrast ratio of: (110 - 0.5) / 0.5 = 219: 1.

With white at 110 cd/sq. m, a contrast of 220: 1 should be enough to reproduce true color. That's a long way from the 400: 1 and more, a value that is bandied around everywhere.

As far as we are concerned, we will now calibrate screens using at least two configurations. We'll start out with the default settings, to check the color rendering with the factory settings. The second stage will consist of gradually diminishing the brightness until it around 110 cd/sq. m while maintaining a very faithful color rendering.

However, unlike Niemetzky, we have opted for a black that was as close as possible to 0.1 cd/sq. m. In our opinion, this just makes the black that much blacker. With our settings, a very good screen ought to produce a contrast ratio of 1099: 1. In practice, the black very rarely achieves less than 0.3 cd/sq. m, although that still gives a contrast of 366: 1.

Gaming

For games, it might be useful to have more brightness. This will have the effect of making the colors more brilliant, offering a rendering that is more appealing to the eye.

Let's assume that you use your screen at 200 cd/sq. m (which is pretty bright).

With black at 0.3 cd/sq. m the ideal contrast ratio would be (200 - 0.3) / 0.3 = 666: 1, which would give a white of 200 cd/sq. m.